Recognising the value of soil biodiversity

The soil beneath our feet and the myriad living organisms within it are vital for human life. Typically, a single gram of soil contains over 5,000 species of microbes. This biodiversity within our soil – the chain of life from bacteria to earthworms and other creatures - provides us with a range of benefits, called ‘ecosystem services’, without which our existence would be impossible. They include the maintenance of soil fertility, the provision of clean water, carbon storage and climate change mitigation.

However, the demands being placed upon global land use, for food, fibre and bioenergy now exceed the amount of land available. The resulting pressure, in the form of intensive farming, is leading directly to a rapid loss of the important soil biodiversity and the services it brings.

This was the background to the set-up of SOILSERVICE, a European Union (EU)-funded research project, which began in 2008. The aim of the project was to analyse the ecosystem services derived from soil biodiversity and to assign clear monetary values to them – something that had never been done before. Once these values had been specified, the benefits of biodiversity could be factored into land management decision-making in a way not previously possible.

In the words of SOILSERVICE’s project coordinator, Professor Katarina Hedlund of Lund University in Sweden, the task which lay at the heart of the three-and-a-half year project, bringing together 11 universities and research institutions from 8 European countries, was to value ‘natural capital’ through the biodiversity within the soil.

“Today, we are deteriorating our natural capital in our urge to have higher yields,” Professor Hedlund says. “But if we can calculate how much money the farmer would earn in conserving rather than exhausting this natural capital, then we can feed this information to policymakers so they can deliver policies that would make farmers self-sustaining instead of giving them subsidies,” explains Professor Hedlund.

The most important evaluation the SOILSERVICE researchers focused on concerned the level of carbon in the soil. If biodiversity is the natural capital of farming, organic carbon can be seen as its currency because it is this which directly determines the amount of life in the soil and hence its fertility. Optimising carbon levels has a clear benefit for the farmer, improving yields and reducing input costs for things like fertiliser. Based on a series of field studies at various European locations, SOILSERVICE calculated that an increase in soil carbon, of roughly 1%, would result in increased profitability for farmers of between €200 and €300 per hectare, depending on their precise location.

Today’s intensive agriculture practices, however, are depleting soil carbon. In other words, by SOILSERVICE’s calculations, they are destroying long-term value. By precisely evaluating the benefits of soil biodiversity, SOILSERVICE introduces a new economic calculation – one which gives due value to the ecosystem services produced by the soil organisms. In the case of soil carbon, the measures needed to maintain soil biodiversity would include permanent plant cover, ploughing plant residues back into the soil and using organic manure. From simple costs, as they would have been regarded in the past, these measures are transformed by the work of SOILSERVICE into investments with an associated return on those investments.

The economic calculations resulting from the work of SOILSERVICE have important implications for policymakers as well as individual farmers. Improved soil biodiversity will deliver public goods as well as private ones including better greenhouse gas control, reduced levels of nitrogen in groundwater, and improved food security. SOILSERVICE’s valuations make it possible to see payments to sustain biodiversity not as subsidies but as long-term investments, building up natural capital in the same way that governments invest in physical infrastructure.

In effect, SOILSERVICE has changed the terms of the land management debate. As Professor Hedlund puts it: “Scientists have known for decades that this is happening in soils. What we have done is put a value on it.”